Cross-fire-neutralizing system



Nov. 22, 1927. -1 649 863 R. B. sHANK CROSS FIRE NEUTRALIZING SYSTEM Filed sept, 18, 1924 INVENTOR Patented Nov. 22, 1927.

UNITED STATES PATENT OFFICE.

ROY B. SHANCK, 0F ELMHURST, NEW YORK, ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAIH COMPANY, A CORPORATIO CROSS-FIBiE-NEUTRALIZING SYSTEM.

Application led September 18, 1924. Serial No. 738,503.

This invention relates to telegraph circuits, and particularly to means. for neutralizing cross-tire between adJacent circuits.

When telegraph impulses are transmitted over one of al plurality oit circuits constituting ay telegraph system,

known as cross-lire circuits ot the syste between the var means have been suc,

cross-tire currents.

disturbing currents are set up in the other m due to the admittance ions circuits. Various Ogested to neutralize the Some ot these arrangements are. intended to neutralize sending end cross-fire,

same end of the which the disturbing signals that is, the cross-tire set up in the of the exposed cirtelegraph system from are being transmitted. Other arrangements are designed to care for receiving end the currents set up ments of the disturbed the distant end of cross-fire, thatis, in the receiving instrucircuits located at the system. One forni of neutralizing arrangement is disclosed in the co-pending which issued Nov.

patent to Cory,

No. 1,560,540, 10, 1925, in which the different transmitter circuits are coupled together so that,

as defined above.

It is the object of to neutralize crosspolar telegraph circuits.

when a signal impulse is them, a neutralizing to the other which end cross-tire the present invention fire between non-duplex By this term is meant a circuit over which transmission can take place 1n only one direction at one time and which employs current reversals to represent marks and spaces. cuit resembles the single line in that transmission direction at vany time, the latter circuit in thatr mitted by reversing the polarity tery applied to the line, opening and closing is well known, aiior Such a` cir-- Morse circuit takes place in only one but it differs from signals are transot the batrather than by the line, and this, as ds better transmission.

rIhe inventionI will be clearly understood from the following description,

when read in connection with the attached drawing, of which Figure 1 shows the embodiment, of

the invention in employing two one-way polar circuits;

aI communication circuit Fig.

2 shows the embodiment of the invention in a system comprisi ng two communication circuits each consisting of a N 0F NEW YORK.

two-way nonduplex pola-r circuit; and Fig. 3 shows the embod iinent of lthe invention cation system comprising more than two v,

in a. communitwo-'way non-duplex polar circuits..

In the arrangement shown in Fig. y1, vthe tongue 2of. the rtransmitter #l is connected with the wire :#:l which extends tothe distant receiving station and terminates there in a polar receiving relay similar to 3,which is connected with wire `.gt/:2.V Likewise, at

the distant station, wire j# 2 is connected the signaling impulses the` distant station.

also has an auxiliary winding nected with the winding 6 former 7, another winding ko are transmitted from This receiving relay 5 which is conot the trans- 'f which, designated 8, is connected between the tongue ofthe transmitter #l and wire :#:L Each oi' the wires, together with transmitter and polar receiv stitutes a one-way polar ci combination of two such circ a complete two-way signaling 'Vhen signaling impulses its associated ing relay, conrcuit, and the uit-sl constitutes circuit.

are sent over wire #l fromthe transmitter #l to the distant station, for example, represented by the solid ing current known as crossarrow,

in the direction thefinterfertire will be set up in wire #2 by virtue of the mutual admittance between the two circuits, which is symbolically represented by the-dotted condenserL connected between the circuits y as shown dotted. This cross-fire current repre-- sented by the wayy arrows will flow directions in wire #2 to which flows toward the tr nected with wire or' will produce no detrimental effect.

hand, the cross-fire current that the other in both ground. That ansmitter con- #2 at the distant end thereilows through receiving relay 3 tends to iiitei'fere with the reception of tion X. By coupling the t cuit of wire #l with oi wire #2,

ing manner: through the neutralizing impulse will'be set signals at staransmitter Acirthe receiving relay this is prevented in the follow- When the signal impulse passes winding 8 oftransformer 7, a

up in winding 6 in the direction represented by the dotted arrow, which flows thr ough the auxilser-ves to neutralize the effect of the crossn transmitter over wire .fc/:1 tothe distant station' in the direction represented by the fire current therein. rlhe magnitude of this. current may be controlled by the looseness or tightness of the coupling of the various windings and alsoby the series and shunt resistances 9 and 10 connected in the neutralizing circuit.

The arrangement shown in Fig. 2 illustrates the application of this principle to two two-way non-,duplex circuits. In this arrangement, cach wire serves not only to transmit' from station X to the distant station but also to transniitl from'the distant station to station X. The proper connection of the wire with the transmitter and the receiving 'polar relay is effected by means of Vthfe switches 11' and 12 which may be either manually operated or controlled automaticallyb'y means ofthe transmitters.` The manner ofdoingthis forms noi part of this inventiona'nd forthe sake of simplicity they will be represented simply as manually operated switches. Vith the'switches thrown in the directions shown in the ligure, the transmitter #l is connected with wire #l toi transmit tothe distant statiomand the receiving relay 13 is connected with wire #2 for receiving signals from the distant station. an auxiliary winding.' connected with a wind-v ing of a' neutralizing transformer, the other winding of which is connected with the' transmitter circuit of the other non-duplex i polareircuit. Thus the auxiliary winding 5 of the polar relay connected with wire :#:1 is connected with the winding 14 of the neutralizing transformer v15, the primary winding 16 of which isconnect'ed with the transmitter of wire #2. In like manner, the auxiliary winding 17 of the relay 13 is connected with the secondary winding 6 of the neutralizing transformer of the other transmitter circuit.

lhen a' signal is being transmitted from solid arrow, the cross-lire currents will be set up in wirev .#12 in the directions represented-v by the wavy arrows. Since signals are being received from wire #2 by the polar relay 13, weneed consider only the cross-lire current that liows theretlnough. lihenever. such .cross-tire current flows, there will at the same instant How through the winding 17 a neutralizing current represented by the dotted arrow, which will be created by the signal impulse iiowingr through the primary winding of transformer 7.v

1When switches. 11 andl 12 are arranged for sendingl on wire #2 and receiving` on wire #1', neutralization of sending end-croissiire from wire .#2 to wire itl e'ected by the transformer l5 and winding 5 of relay 4, in a manner similar to that just described'.

Each of the receiving relays has retenes The arrangement of' Fig. 3 shows the application of the invention to' a system consisting of more than two two-way nonduplexpolar circuits. Specifically, three circuits are shownwhich require three trans former-s at each end thereof, those at stat-ion X being designated A, B and C and those` at station Y A', B and C. wWith the switches G, Vl-l and I and Gr, H and lrin the posit-ions shown in the drawing, the circuits are arranged vfor transmission over wires ,tl .and from left to right and over wire :gt3 from right to left. The direetions of the sional im )ulses are re re-V e l P sented by the'solid arrows. 'lfheflow of signaling current over `wire #l will produce cross-lire in relay Ev and relay F. The cross-tire eifect in relay F is neutralized by the neutralizing current, represented by the dot-ted line, setl up in the auxiliary winding of the relay by the potential induced in winding K of transformer A. In relay Ef the cross-lire is neutralized by the neutralizing current, shown bythe dottedarromproduced in wire .#2 and iiowingjthrougli thev station Y, having the same letters primed,

will effect neutralization ofcross-fire'in a si mi lar manner.

lYhile this invention has been disclosedl as embodied in. a particular form, it is toi be understoodthat it is capable of embodiment in other forms without departinggfrom the spirit and scope of the appended claims.

lVhat is claimed is: 1. In a cross-lire neutralizing system, the combination'witha line having at the home station a transmitter connected thereto 0fasecond line having` at the same station as the first line a polar relay connected thereto, and. an inductive coupling between Said transmitter and the windingofthe saidpolar relay toneutralize tl1e,cr0ssiire inthe said` relay resulting from" the transmission of signals yover the Vsaid irstline. 1

the cross-lire in the said relays resulting from the transmission of signals over the said first line.

3. In a cross-fire neutralizing syst-em, the combination with a plurality` of lines each having at each end a transmitter and a polar relay associated therewith, of switching means to connect a line either with its transmitter or with its receiving relay, and inductive couplings between the vtransmitter of each line and the winding of each of the lpolar relays of the other lines to neutralize cross-fire in the relay of one line resulting from the transmission of signals over the said other line.

4f. In a cross-lire neutralizing system, the combination with a plurality of lines each having at each end a transmitter and a polar relay associated therewith, each relay having a main andan uxiliary winding, of switching means to connect `either the Said transmitter or the main winding'of the relay with the line to which-the said transmitter and relay are individual, and inductive couplings between the transmitter of each line and the auxiliary windings of the relays of the other lines to neutralize cross-fire in any -line resulting from the transmission of sig-v nals over another line. v

In testimony whereof, I have signed my name tovthis specificationy this 16th day of September, 1924:.

ROY B. -SHANCK. 

